In U.S. Pat. No. 3,771,194 there is disclosed an improved construction for permitting a cover mounting hinge and counterbalance mechanism of the type disclosed in U.S. Pat. No. 3,187,374 to be installed for purposes of mounting a cover on a cabinet without necessitating adjustment of a counterbalance spring device. More specifically, U.S. Pat. No. 3,771,194 contemplates the utilization of a retainer adapted to be inserted in the mechanism in a manner providing for precompression of a counterbalance spring device sufficient to permit the cover and cabinet hinge parts to undergo free or noncounterbalance movements during installation of the mechanism. After installation, the retainer is removed to permit the compression spring device to become effective for counterbalance purposes.
A retainer device of the type contemplated by U.S. Pat. No. 3,771,194 is, however, not readily adapted for use in more basic counterbalance supports of the type employing a counterbalance spring device whose opposite ends are directly connected to a pair of hinge parts by pivot devices, such as that disclosed for instance in U.S. Pat. Nos. 2,257,791 and 3,330,593 (FIG. 3).